1981 Unknown Engine Internals, Compression Test?
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Joined: Mar 2010
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From: Fort Worth Texas
1981 Unknown Engine Internals, Compression Test?
I bought a 1981 C3 a few weeks ago. The seller said the engine had been rebuilt 10k miles earlier by the owner before him but had no idea what had been done to it. It runs great and feels like it has tons of power, but all I know is it has a "bigger" cam. How can I check the actual compression ratio without tearing into it to find out what internals were used? I would like to do some performance stuff to it but want to know where I'm at with what I have so I know what upgrades to do. If compression is still low like it was from factory I will look at doing the 58cc L-98 heads first then do intake/carb/etc. Just out of curiosity, if I go with the aluminum L-98 58cc heads, will my accessory stuff bolt straight on, and should it work with my headers/side pipes currently on my car? Thanks guys!
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You cannt tell the actual compression ratio without tearing into it. A high compression engine with a radical cam will give low numbers during a compression test just like a low compression engine. You can try removing the valve cover and use a dial indicator to determine some characteristics of the cam. Checking the head casting numbers will tell you what heads are on the car low or high compression but wont tell you if the pistons were changed.
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From: New Or-leens Loo-z-anna
You cannt tell the actual compression ratio without tearing into it. A high compression engine with a radical cam will give low numbers during a compression test just like a low compression engine. You can try removing the valve cover and use a dial indicator to determine some characteristics of the cam. Checking the head casting numbers will tell you what heads are on the car low or high compression but wont tell you if the pistons were changed.
